code: def test_rich_club_exception2():
      with pytest.raises(nx.NetworkXNotImplemented):
          G = nx.MultiGraph()
          nx.rich_club_coefficient(G)
  
file_path: networkx/networkx/algorithms/tests/test_richclub.py
imports: import pytest
  import networkx
label_desc: Use image node_id 8 for calling a global function with example usage: test_rich_club_exception2() without return types